Plug structure



'7 March 5, 1945.

M. P. LAURENT PLUG STRUCTURE Filed April 2, 1945 INVENTOR.

' Patented Mar. 6, 1945 NT I PLUG STRUCTURE Milton P. LaurentHouston, Tex.

This invention relates to plugs and has for its general object the provision of an improved plug for use in holding high pressure at high tempera- I tures.

The plug to which this invention relates is of general application wherever a plug is required for closing anopening against relatively high pressures at elevated temperatures. Specifically the embodiment herein disclosed is designed for the particular purpose of providing closure members for the clean-out openings of. headers and Application April 2 1943, SerialNo. 481,580

4 Claims. (01. 220 450) f I I Fig.2 is an end elevation of the samestructure with parts broken away and shown-in cross sectionfor purposes of illustration,

[ Fi'g. 3 is a fragmentary cross sectional view taken along the line 3-3 of Fig.;

Referring more in detail to the drawing, the numerals I and 2 indicatea. pair of tubes or tubular members which are substantially parallel to each other'and which are-joined together at particularly box type headers such'as are employed in connecting the adjacentends of tubular members in a boileror otherheat exchange apparatus.

In the past these clean-out openings have been closed by means of tapered plugs held in place against tapered seats by any one of' a number of well known holding devices. Prominent among these was astirrup like yoke having parts extending from. the exterior of the header on both sides of the opening in the header and having a cross member extending over the opening carrying a set screw adapted to bear against theplug and hold it in place. Difficulties have been encountered with this structure, however, in that when excessive pressure is appliedto such 'a plug it tends to lift the plugfrom its seat and hence to produce a leak. When high pressures are com- I bined with high temperatures this tendency is all themore prominent because of the fact that the .material of the plug itself has less strength at high temperatures and is, therefore, more apt to take a permanent set, which, of course, will mean thattheplug will thereafter not. provide a tight seal for the opening.

It is, therefore, an object-of this invention to provide a plug structure andholding means thereforwhich will not loosen under high pressures and temperatures.

Furthermore, it is an object of this invention to provide such a structure in which the seal will actually become tighter and more perfect asthe device is subjected to 'greater' pres.

sures and higher temperatures, this being true, of course, within the physical limitsofthe mate rial of which the structure is made. 7

Another object of thisinvention is to provide a plug which will give greater strength per unit of its weight than would plugs of the previously used designs. .7 v

Other objects andadvantages .of'this inven-" tion will become apparent from the following description taken in connection'with the accompanying drawing in which. one embodiment'of and example.

In the drawing: u Fig. l is a view partly in longitudinal cross section and partly in side elevation illustrating a. plug structure made in accordance with this invention. Q

this invention is set forth by way of illustration their adjacent ends by'means of the header 3.

,Th'eheader 3 is provided-with appropriate openlugs for receiving the ends of, the tubes l and 2 andthese tube ends are rolledfintosuchopenings and into circumferentialcorrugations 4 formed in, such openings asindicated by, the numeral 5. In order that accessmight behad to the interior of the openinglin the: header and of the tubular member fitting therein so that this rolling operation just referred to might be carrieciout and also so that access might bejhad to the interiorof the tubular. member and the header for clean-out purposes the header is provided in alignment with the tubular member with. an opening known as a clean-out opening having a tapered plug seat 6, Seated against this tapered plug seat 6 is the tapered peripheral posed outwardly-with respect tothe header O-n I itsoute'r edge the tapered seat Ill-is provided for seating, against the surface 6 within the opening'in the headenthese two seating surfaces being-preferably groundtogether for the purpose of securing a perfect joint. As illustrated, these seating surfaces are conical although it is conceivable thatthey .m'ght bemade spherical if desired. f The marginal portion ofthe plug member is preferably formed with an outwardly turned part or lip, and on the inner surface of this lip is provided a bearing or seating surface, this second surface being of spherical formation as shown at II. Against; this spherical surface II there is adaptedto be seated a'corresponding spherical surface I2 on a hold down nut I3; The purpose of providing the spherical surfaces II, and I2 is so that the hold down member I3 might adjust itself withjrespect to the plug 1 without disturbing the seating of the plug I upon the seat 6.

The hold down member I3- is provided on its outer marginal portion with inclined ears or lugs correspondingly I4 adapted to engage beneath formed lugs opening in the'header. As will be'seen by ref erence to Fig. 2 the lugs I4 and I5 are spaced apart circumferentially so that the lugs I4 may fit between the lugsl5 after which the member I3 maybe rotated until the lugs I4 engage be.. neath the, lugs I5 and erve to wedge the mem- .I5 within the outer portion of the ber l3 against its seat on the plug 1 to hold the same in place.

It is further noted that the plug 1 has an upstanding stemalli projecting outwardly from its central portion with an opening I! formed in this stem thus providing a means whereby the plug 1 may be forcibly removed from its seat when desired. The hold down member I3 is provided with a central opening l8 loosely embracing the stem 16.

The hold down member with an outwardly and laterally extending arm 19 having an opening 20 adjacent its outer end. This arm I9 is adapted to extend toward and overlap theend 'of a similar arm 2| on an adjacent plug hold down member 22 on thesame header, with the opening 23 in such arm 2| registering substantially'with the opening 20 in the arm l9. Through these two openings 20 and 23 there is then placed a bolt 244 having a head 25 on one end and a nut 26 on the other, so that upon tightening this nut and bolt the two arms [3 is' also provided outer portion of said opening and having parts engageable with the marginal portions of said disk like member on the concave side thereof to prevent bodily movement of said disk like memher away from its seat under influence of preswill be drawn toward each other to tighten the two hold down members 13 against their respective plugs. 1 I

From the foregoing it will be seen that the space between the seat '6 in the clean-out opening and the surface l2 on the hold down mem- -i ber i3 is an annularwedge-shaped space and that the marginal lip on the plug 1 forms a wedgeshaped member fitting such space. It will further be seen that since the hold down member i3 bears against the marginal portion of the plug and the plug isof concavo-convex formation with the convex side toward the pressure, any tendency of the plug to yield under pressure will cause a spreading of its marginal portions and thus cause the plug to bear more tightly against the seat i. This effect will be accentuated by theiact 'thatthe marginal lip portion is being forced into a wedge-shaped space thus causing it to fit more and more tightly against both the surface =6 and the surface [-2. Furthermore, it

will be seen that the result just-described will follow regardless of whether the deformation of the plug is due solely to pressure or is due to a yielding of the plug because of a weakening thereof under high temperature conditions.

In addition to the foregoing it will be noted that the plug being formed .in .a concavo-convex shape provides-a dome support against the pressure within the header-an thus provides great strength in the plug with a relatively small amount of material used ztherein. .Thus the weight of the :plug may be :reduced. for :a :given strength. l i

It will thus be seen that "a means has been provided for marrying out and accomplishing. all of the obj ects'sought by this invention.

. .Having described myinvention, I .claim:

-1. In a plug structure a concave-convex disk like member having aseat about its outer edge toiorm a seal within-an "opening and be'ing adapted to have its convex side exposed to high pressure, and means engageable with the marginal portions of said member on the concave side thereof to prevent bodily movement of said member under influence of sign pressure, the surface of contactbetweeri said means and memher-being spherical whereby said-means may adjust itself 'to bear at all times-evenly against the marginal portions of said' member and whereby pressure on themonvex side of saidmember will tend to aiiatten .it and cause said marginal ore sure on the convex side thereof, whereby pressure on the convex side of said disk like member will tend to flatten it and cause .said marginal portions to expand into tighter sealing engagement with the seat on the wall of said opening.

3. In a plug structure, a member having an opening therein and having the walls of said opening'formed with a seat for a plug for closing said opening, a plug member having a seat about its outer edge to engage and form a seal with the seat within said opening and being adapted to have one of its faces exposed to high pressure, and means separate :from said member and engageable'with the marginal portions of the opposite face ofsaid member to prevent bodily movement thereof under the influence oisuch pressure, said last mentioned means having itsportion which contacts with said plug member so shaped as to provide a wedge-shaped space between said portion which contacts the plug memher and the seat Within said opening, and the marginal portion of said plug member with which said means engages being in the form of a liplike flange extending in the direction in which such pressure would tend to force said plug member, said lip-like flange having formed on its outermost surface the seat portion which is adapted to seat within said opening and on its inner surface a portionadapted to be engaged by.

said means engageable with the plug member, said lip-like flange between said portions being of wedge-like formation to 111; 'within said wedgeshaped space, whereby pressure on the said plug member will tend 1130 wedge .said lip-like portions into said wedge-shaped space and into tighter sealing engagement with the seat in said opening. I 4. In .a .plug structure, in acombination with a chamber having an opening in the wall thereof and an outwardly tapering .conical seat in said opening "a concavoeconvex disk like member having 'a tapered conical seat about its outer-edge to seat upon said seat within the opening and form a seal therewith when its convex side is disposed toward the interior of said member, and means separate from said chamber and anchorable 'withinithenuter'portion of said opening and having'parts engageable with the marginal portions of said disk like member on the concave side thereof to prevent bodily movement of said disk like member away from its seat under the influence of pressure :on .the convex side thereof, whereby pressure on the convex side of said disk like member will tend to flatten it and cause said marginal portions to expand into tighter sealing engagement with the seat on the wall of said opening.

MILTON P. LAURENT. 

